The Senate needs to rule on the evidence used in the impeachment. If the Democrats have other evidence they should have taken the time to present it during the House impeachment process as that was the place to do it. Further the House impeachment process was in itself one sided and unfair. These rules insure a fair hearing based on the material used to impeach. Any withheld material is irrelevant. The House should have done a better and more fair job, taking the time to present all the evidence needed when they made their case. They deliberately did not, knowing full well what the final outcome would be so they could say they did what they promised to do and keep the fires stocked and create a cloud around the 2020 election. Furthermore, by holding onto the un-presented and unknown evidence they will be able to start yet another impeachment to go into the election year with. Can't wait to vote out as many obsessive, one track minded Democrats as possible.